1. Field of the Invention
The present invention relates to an earphone, and more particularly, to an earphone which is capable of protecting a user's tympanic membrane, improving the durability thereof, and enjoying the further improved quality of sound by adjusting a medium-low pitched sound.
2. Description of the Related Art
Most recent portable terminals are designed such that users can use the functions of an MP3 player and a PMP, as well as the call function, and can enjoy various media contents combined with audios and videos. For enjoying ample volumes of such portable terminals, an earphone is an essential item.
In general, an earphone is mounted with an elastic earpiece on an outer surface of a housing. A diaphragm is disposed in a speaker toward a side where the earpiece is mounted, and the speaker is embedded in the housing. When the above-described earpiece comes into close contact with a user's external auditory canal, the earphone transmits a sound to the user.
However, if the general earphone having such a structure is used in close contact with the user's external auditory canal for a long period of time, the user may feel pain and uncomfortable at his or her external auditory canal, and the user's tympanic membrane may be badly affected.
Therefore, from the above-described point of view, there have been proposed technologies that maintain a pressure balance between an inner space of a housing and an inner space of an external auditory canal closely contacting an earpiece by forming a small hole communicating with the inner space in an outer surface of the housing close to the earpiece, thereby reducing pain the user may feel.
However, due to the structure of the housing through which the small hole penetrates, the earphone having the above-described structure causes loss of a medium-low band and causes a considerable change over an entire frequency band of a sound. As a result, problems such as a tone distortion arise.